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→Key Stage 4
===Calculating Electrical Power===
{| class="wikitable"
| style="height:20px; width:200px; text-align:center;" |An electrical fan is plugged into a [[Electrical Socket|socket]] supplying 230V. An [[ammeter]] reading shows that the [[Electrical Current|current]] going into the fan is 0.20amps. Calculate the power of the fan correct to two [[Significant Figures|significant figures]].
| style="height:20px; width:200px; text-align:center;" |A light bulb is supplied a current of 625mA. The [[Potential Difference|potential difference]] across the terminals on the [[Electrical Bulb|light bulb]] is 96 [[volt]]s. Calculate the [[power]] of the [[Electrical Bulb|bulb]] correct to two [[Significant Figures|significant figures]].
| style="height:20px; width:200px; text-align:center;" |A [[Electrical Kettle|kettle]] is plugged into the [[Mains Electricity|mains supply]] which operates at 230V. It receives a current of 9.2Amps Calculate the power of the kettle correct to two [[Significant Figures|significant figures]].
|-
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
I = 0.20A
V = 230V
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
I = 625mA = 0.625A
V = 96V
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
I = 9.2A
V = 230V
|-
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>P = IV</math>
<math>P = I \times V</math>
<math>P = 0.20 \times 230</math>
<math>P = 46W</math>
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>P = IV</math>
<math>P = I \times V</math>
<math>P = 0.625 \times 96</math>
<math>P = 60W</math>
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>P = IV</math>
<math>P = I \times V</math>
<math>P = 9.2 \times 230</math>
<math>P = 2116W</math>
<math>P \approx 2100W</math>
|}